Superbugs in India - April 8

Superbug gene rife in Delhi water supplySarah Boseley, Guardian A gene that causes a wide range of bacteria to become resistant to antibiotics has been found in the water supply in Delhi, with worrying implications for the rest of the globe.

International travel and medical tourism have already brought the gene, known as NDM-1, to the UK. A team of scientists reported last year that they had found NDM-1 positive bacteria in a small number of patients who had visited India for kidney or bone marrow transplants, dialysis, pregnancy care or burns treatment, while others had undergone cosmetic surgery.

A paper by Timothy Walsh from Cardiff University and colleagues, published in the Lancet Infectious Diseases journal, reveals that the gene, known as NDM-1, is widespread in the water used for cooking, washing and drinking in Delhi. (7 April 2011)

WHO Calls for Action on Superbugs Sten Stovall, Wall Street Journal A form of superbug that gives bacteria the power to resist virtually all known antibiotics may be spreading, posing a global health risk, health experts warned Thursday.

Called New Delhi metallobeta-lactamase, or NDM-1 for short, the enzyme destroys carbapenems, an important group of antibiotics used for difficult infections in hospitals, and has been found in a wide variety of bacterial types.

British researchers in August reported that infections involving NDM-1 had been found in patients in Bangladesh, India, Pakistan and Britain.

New research published Thursday in the U.K. medical publication The Lancet shows NDM-1 is widespread in sewage and drinking water outside the hospital environment in Delhi, India, circulating because of sewage contamination in bacteria that inhabit drains and tap water.

The World Health Organization issued a plea Thursday for collective action to fight emerging superbugs like NDM-1, warning that the threat is spreading fast. (7 April 2011)

Lancet study finds waterbugs in New DelhiAditi Tandon, Tribune (India) NEW DELHI. India today rejected as “unscientific” and “discriminatory” a new Lancet study which claims to have traced to New Delhi’s drinking water and seepage chain 11 fresh strains of antibiotic-resistant bacteria causing cholera and dysentery. The research calls these bacteria “waterbugs”, says these are resistant to all existing antibiotics; and seeks studies in Pakistan and Bangladesh to determine their prevalence.

Published in the ‘Lancet Infectious Diseases Journal’ two days ago and led by Professor Tim Walsh of the Cardiff University School of Medicine, the study is an extension of the past controversial research (also carried by the Lancet Online in August 2010) which had similarly claimed the discovery of a drug-resistant superbug to India’s capital. The researchers had then named the gene carrying these bacteria as NDM-1 after New Delhi - a move for which the Lancet Online editor Richard Horton later apologised during his India visit.

Within two months of that public apology, the Lancet has again published a fresh European Union-funded study which the government today described as another attempt to “keep the heat on India and single it out for motives other than scientific”.

Secretary Health Research Dr VM Katoch lambasted the research as ‘insignificant and with zero public health consequences for Indians and visiting foreigners’. He objected to the four British authors’ sampling of the water from India without the mandatory clearance from the Health Ministry. “This is illegal; biological materials can’t be exported without permission. We will take up this matter,” Katoch said.

The authors of the study say they conducted it after discovering NDM-1 gene (which enables Gram-negative bacterial strains to become resistant to carbapenem, a powerful antibiotic) in patients who had not been hospitalised during their India visits. They claimed the presence of water bugs in India’s environment, insinuating that India’s waters were contaminated. (7 April 2011)

Antibiotic resistance: Bacteria are winning the warFrank Swain, Guardian n what has surely become the most ritualised medical practice since the Hippocratic Oath, the World Health Organization took to the stage again today to warn that the misuse of antibiotics was threatening to render one of our most potent medicines useless. This comes a decade after an identical appeal from the organisation warned of a global crisis in the making.

Health experts have been ringing the alarm over antimicrobial resistance for so long that it seems to have become part of our collective background noise, like the endless rasp of waves on the shore. And like stupid tourists, we sleep in the sun while the tide comes in.

It might surprise you to learn that resistance to antibiotics was identified even before Fleming's wonder drug hit the shelves. The first clinical application of penicillin came in the early 1940s, but the discovery of beta-lactamase – a bacterial enzyme capable of destroying penicillin – preceded that revolution by a few years. The microbes were always one step ahead. As early as 1960, it was clear that overuse of antibiotics was driving the emergence of resistant species.

We also knew how to combat the problem: restricting the use of antimicrobials, ensuring patients completed their courses, containing outbreaks of resistant species. (7 April 2011)

Background Not all patients infected with NDM-1-positive bacteria have a history of hospital admission in India, and extended-spectrum β-lactamases are known to be circulating in the Indian community. We therefore measured the prevalence of the NDM-1 gene in drinking water and seepage samples in New Delhi.

Methods Swabs absorbing about 100 μL of seepage water (ie, water pools in streets or rivulets) and 15 mL samples of public tap water were collected from sites within a 12 km radius of central New Delhi, with each site photographed and documented. Samples were transported to the UK and tested for the presence of the NDM-1 gene, blaNDM-1, by PCR and DNA probing. As a control group, 100 μL sewage effluent samples were taken from the Cardiff Wastewater Treatment Works, Tremorfa, Wales. Bacteria from all samples were recovered and examined for blaNDM-1 by PCR and sequencing. We identified NDM-1-positive isolates, undertook susceptibility testing, and, where appropriate, typed the isolates. We undertook Inc typing on blaNDM-1-positive plasmids. Transconjugants were created to assess plasmid transfer frequency and its relation to temperature.

Findings From Sept 26 to Oct 10, 2010, 171 seepage samples and 50 tap water samples from New Delhi and 70 sewage effluent samples from Cardiff Wastewater Treatment Works were collected. We detected blaNDM-1 in two of 50 drinking-water samples and 51 of 171 seepage samples from New Delhi; the gene was not found in any sample from Cardiff. Bacteria with blaNDM-1 were grown from 12 of 171 seepage samples and two of 50 water samples, and included 11 species in which NDM-1 has not previously been reported, including Shigella boydii and Vibrio cholerae. Carriage by enterobacteria, aeromonads, and V cholera was stable, generally transmissible, and associated with resistance patterns typical for NDM-1; carriage by non-fermenters was unstable in many cases and not associated with typical resistance. 20 strains of bacteria were found in the samples, 12 of which carried blaNDM-1 on plasmids, which ranged in size from 140 to 400 kb. Isolates of Aeromonas caviae and V cholerae carried blaNDM-1 on chromosomes. Conjugative transfer was more common at 30°C than at 25°C or 37°C.

Interpretation The presence of NDM-1 β-lactamase-producing bacteria in environmental samples in New Delhi has important implications for people living in the city who are reliant on public water and sanitation facilities. International surveillance of resistance, incorporating environmental sampling as well as examination of clinical isolates, needs to be established as a priority. (7 April 2011)A study on which the Guardian article is partly based. Available online for those who sign up. -BA

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